<template>
  <a-cascader
    v-model:value="state"
    :options="options"
    :load-data="loadData"
    change-on-select
    @change="handleChange"
    :displayRender="handleRenderDisplay"
  >
    <template #suffixIcon v-if="loading">
      <LoadingOutlined spin />
    </template>
    <template #notFoundContent v-if="loading">
      <span>
        <LoadingOutlined spin class="mr-1" />
        {{ t("component.form.apiSelectNotFound") }}
      </span>
    </template>
  </a-cascader>
</template>
<script lang="ts">
import { defineComponent, PropType, ref, unref, watch, watchEffect } from "vue";
import { Cascader } from "ant-design-vue";
import { propTypes } from "/@/utils/PropTypes";
import { isFunction } from "/@/utils/Is";
import { get, omit } from "lodash-es";
import { useRuleFormItem } from "/@/hooks/component/UseFormItem";
import { LoadingOutlined } from "@ant-design/icons-vue";
import { useI18n } from "/@/hooks/web/UseI18n";

interface Option {
  value: string;
  label: string;
  loading?: boolean;
  isLeaf?: boolean;
  children?: Option[];
}

export default defineComponent({
  name: "ApiCascader",
  components: {
    LoadingOutlined,
    [Cascader.name]: Cascader
  },
  props: {
    value: {
      type: Array
    },
    api: {
      type: Function as PropType<(arg?: Recordable) => Promise<Option[]>>,
      default: null
    },
    numberToString: propTypes.bool,
    resultField: propTypes.string.def(""),
    labelField: propTypes.string.def("label"),
    valueField: propTypes.string.def("value"),
    childrenField: propTypes.string.def("children"),
    asyncFetchParamKey: propTypes.string.def("parentCode"),
    immediate: propTypes.bool.def(true),
    // init fetch params
    initFetchParams: {
      type: Object as PropType<Recordable>,
      default: () => ({})
    },
    // 是否有下级，默认是
    isLeaf: {
      type: Function as PropType<(arg: Recordable) => boolean>,
      default: null
    },
    displayRenderArray: {
      type: Array
    }
  },
  emits: ["change", "defaultChange"],
  setup(props, { emit }) {
    const apiData = ref<any[]>([]);
    const options = ref<Option[]>([]);
    const loading = ref<boolean>(false);
    const emitData = ref<any[]>([]);
    const isFirstLoad = ref(true);
    const { t } = useI18n();
    // Embedded in the form, just use the hook binding to perform form verification
    const [state] = useRuleFormItem(props, "value", "change", emitData);

    watch(
      apiData,
      (data) => {
        const opts = generatorOptions(data);
        options.value = opts;
      },
      { deep: true }
    );

    function generatorOptions(options: any[]): Option[] {
      const { labelField, valueField, numberToString, childrenField, isLeaf } = props;
      return options.reduce((prev, next: Recordable) => {
        if (next) {
          const value = next[valueField];
          const item = {
            ...omit(next, [labelField, valueField]),
            label: next[labelField],
            value: numberToString ? `${value}` : value,
            isLeaf: isLeaf && typeof isLeaf === "function" ? isLeaf(next) : false
          };
          const children = Reflect.get(next, childrenField);
          if (children) {
            Reflect.set(item, childrenField, generatorOptions(children));
          }
          prev.push(item);
        }
        return prev;
      }, [] as Option[]);
    }

    async function initialFetch() {
      const api = props.api;
      if (!api || !isFunction(api)) return;
      apiData.value = [];
      loading.value = true;
      try {
        const res = await api(props.initFetchParams);
        if (Array.isArray(res)) {
          apiData.value = res;
          return;
        }
        if (props.resultField) {
          apiData.value = get(res, props.resultField) || [];
        }
      } catch (error) {
        console.warn(error);
      } finally {
        loading.value = false;
      }
    }

    async function loadData(selectedOptions: Option[]) {
      const targetOption = selectedOptions[selectedOptions.length - 1];
      targetOption.loading = true;

      const api = props.api;
      if (!api || !isFunction(api)) return;
      try {
        const res = await api({
          [props.asyncFetchParamKey]: Reflect.get(targetOption, "value")
        });
        if (Array.isArray(res)) {
          const children = generatorOptions(res);
          targetOption.children = children;
          return;
        }
        if (props.resultField) {
          const children = generatorOptions(get(res, props.resultField) || []);
          targetOption.children = children;
        }
      } catch (e) {
        console.error(e);
      } finally {
        targetOption.loading = false;
      }
    }

    watchEffect(() => {
      props.immediate && initialFetch();
    });

    watch(
      () => props.initFetchParams,
      () => {
        !unref(isFirstLoad) && initialFetch();
      },
      { deep: true }
    );

    function handleChange(keys, args) {
      emitData.value = keys;
      emit("defaultChange", keys, args);
    }

    function handleRenderDisplay({ labels, selectedOptions }) {
      if (unref(emitData).length === selectedOptions.length) {
        return labels.join(" / ");
      }
      if (props.displayRenderArray) {
        return props.displayRenderArray.join(" / ");
      }
      return "";
    }

    return {
      state,
      options,
      loading,
      t,
      handleChange,
      loadData,
      handleRenderDisplay
    };
  }
});
</script>
